One change we have made when you'd like to code with v4 for your apps is that now each API call returns more helpful information but in a slightly different format. All the responses you get from your Fiery servers are "wrapped". See the example below,

So if you'd like to use v4 for your existing apps, there are some minor changes you have to make.

Please keep in mind that upgrading your Fiery servers with the latest Fiery API version 4 install doesn't require you to make changes to your apps. You can keep using your existing apps (that are using v3 or v2) without making any changes to your code.